[dev/syn2] Allow other attributes in #[pin_data] structs

Cargo.toml

@@ -32,6 +32,7 @@ trybuild = { version = "1.0", features = ["diff"] }
 macrotest = "1.0"
 # needed for macrotest, have to enable verbatim feature to be able to format `&raw` expressions.
 prettyplease = { version = "0.2", features = ["verbatim"] }
+test_dummy_only = { path = "./test_dummy_only" }
 
 [lints.rust]
 non_ascii_idents = "deny"

internal/src/pin_data.rs

@@ -162,7 +162,7 @@ fn generate_unpin_impl(
         .cloned()
         .collect::<Vec<_>>();
     for field in &mut pinned_fields {
-        field.attrs.retain(|a| !a.path().is_ident("pin"));
+        field.attrs.retain(keep_attr);
     }
     quote! {
         // This struct will be used for the unpin analysis. It is needed, because only structurally
@@ -267,7 +267,7 @@ fn generate_projections(
              ..
          }| {
             let mut attrs = attrs.clone();
-            attrs.retain(|a| !a.path().is_ident("pin"));
+            attrs.retain(keep_attr);
             let mut no_doc_attrs = attrs.clone();
             no_doc_attrs.retain(|a| !a.path().is_ident("doc"));
             let ident = ident
@@ -348,6 +348,16 @@ fn generate_projections(
     }
 }
 
+fn keep_attr(attr: &syn::Attribute) -> bool {
+    let path = attr.path();
+
+    if path.is_ident("pin") {
+        return false;
+    }
+
+    path.is_ident("doc") || path.is_ident("cfg")
+}
+
 fn generate_the_pin_data(
     ItemStruct {
         generics,
@@ -376,7 +386,7 @@ fn generate_the_pin_data(
         pinned: bool,
     ) -> TokenStream {
         let mut attrs = attrs.clone();
-        attrs.retain(|a| !a.path().is_ident("pin"));
+        attrs.retain(keep_attr);
         let ident = ident
             .as_ref()
             .expect("only structs with named fields are supported");

test_dummy_only/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "test_dummy_only"
+version = "0.0.1"
+edition = "2021"
+
+authors = ["y86-dev"]
+license = "MIT OR Apache-2.0"
+description = "Proc macro only for test reproduction."
+
+publish = false
+
+[lib]
+proc-macro = true

test_dummy_only/src/lib.rs

@@ -0,0 +1,4 @@
+#[proc_macro_derive(Dummy, attributes(dummy_attr))]
+pub fn derive_device(_: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    proc_macro::TokenStream::new()
+}

tests/extra_attrs.rs

@@ -0,0 +1,23 @@
+#![cfg_attr(not(RUSTC_LINT_REASONS_IS_STABLE), feature(lint_reasons))]
+
+use pin_init::*;
+use test_dummy_only::Dummy;
+
+#[pin_data]
+#[derive(Dummy)]
+struct Pointless {
+    #[pin]
+    #[dummy_attr]
+    #[cfg(test)]
+    member: i8,
+    #[pin]
+    #[dummy_attr]
+    #[cfg(not(test))]
+    member: u8,
+}
+
+#[test]
+fn multiple_attributes() {
+    stack_pin_init!(let p = init!(Pointless { member: 0 }));
+    println!("{}", p.member);
+}